This machine includes a horizontal receiving surface which is constituted by the bottom of a vat, the vat having a width and a length, and a device for supplying and spreading a suspension which includes a suspension applicator and an external tank, the applicator including a suspension reserve fed from the external tank, at least one vacuum-forming device in the reserve and at least one hole connected to the reserve and formed facing the surface the vacuum forming device being controlled to regulate the amount of suspension released from the hole, the applicator being arranged along the width of the vat and having at least the printing width and being configured to translate along the length of the vat to be able to apply suspension through the hole onto the surface.
|
1. A machine for manufacturing parts by the stereolithography technique, according to which layers of radiation-curable suspension are successively cured one on top of the other by irradiation according to a pattern defined for each layer, said machine comprising:
a horizontal receiving surface, configured to receive the first layer and subsequent layers formed on top of each other from the first layer;
a supply and spreading device configured to, at each layer formation, supply a quantity of suspension and spread the suspension on said horizontal receiving surface for the first layer, and on each previously cured patterned layer for each of the subsequent layers, the supply and spreading device and the horizontal receiving surface being movable relative to each other in the direction of layer stacking; and
an irradiation device for irradiating each layer after said layer has been spread to cure said layer in the previously defined pattern,
wherein the horizontal receiving surface is constituted by the bottom of a vat, said vat having a length and a width, and wherein said supply and spreading device comprises a suspension applicator and an external tank, the suspension applicator comprising a suspension reserve fed from the external tank, at least one vacuum forming device in the suspension reserve and at least one hole connected to the suspension reserve and formed facing the horizontal receiving surface, said at least one vacuum forming device being controlled to regulate the amount of suspension released from said at least one hole, the suspension applicator being disposed along the width of the vat and having at least the printing width and being configured to translate along the length of the vat to be able to apply suspension through said at least one hole onto the receiving surface, wherein the applicator is a rectangular parallelepiped and has an active face, the active face facing the horizontal receiving surface, the active face being a release face of the applicator in which said at least one hole is formed.
2. The machine according to
3. The machine according to
4. The machine according to
5. The machine according to
6. The machine according to
7. The machine according to
8. The machine according to
9. The machine according to
10. The machine according to
11. The machine according to
12. The machine according to
13. The machine according to
14. The machine according to
15. The machine according to
16. The machine according to
|
This application claims priority to FR Application No. 2012228, filed Nov. 26, 2020, the entire contents of which is hereby incorporated by reference.
The present invention relates to a machine for the manufacture of green parts of ceramic or metallic material by stereolithography, such green parts being intended to be subjected to cleaning, debinding and sintering operations to obtain finished ceramic or metallic parts.
Stereolithography generally involves the following steps to obtain these green parts:
Then, as mentioned above, to obtain the finished part, the green part is cleaned to remove the uncured composition; the cleaned green part is debinded; and the cleaned and debinded green part is sintered to obtain the finished part.
The curable composition may be in the form of a suspension. The rigid support is a working plate supporting the various layers of the part being built and the suspension, and each of the layers is generally formed by lowering the working plate and spreading a predefined thickness of suspension. A supply of suspension is stored in tanks (vats or cartridges or pressure pots) which are automatically emptied of a predefined amount of suspension at each layer. This creates a bead of suspension to be spread on the top layer of the part being manufactured which will have been previously lowered by the working plate. Each layer is usually spread by a scraper that sweeps the working surface of the working plate, for example by moving in a straight horizontal direction.
Each time a layer is formed, the strand emerges from its tank to extend across the width of the plate between the plate and the scraper to a height calculated so that the plate can be covered with the suspension forming the layer as the scraper advances.
This system is not feasible for large machines because:
It was proposed by the Applicant that the suspension should be fed through a nozzle in front of the scraper over its entire width. While this solution solves the problem of width distribution, the problem of length distribution remains to be solved for large plates, as the continuous supply of suspension during the movement of the scraper is made more complicated. If the scraper is stopped at certain times to apply a new suspension strand, surface defects on the parts, i.e. marks at the location of the stops, are generated; and if a continuous suspension strand is applied in front of the scraper, this operation is difficult to control over the entire width during the entire advance of the scraper, leading to the application of more suspension than necessary, generating additional efforts.
To overcome these disadvantages, the Applicant proposed that the supply and spreading of the suspension on the horizontal receiving surface for the first layer and on each layer with a previously cured pattern for each other layer should be carried out by an applicator system with a suspension reserve fed from an external tank, the stacking of layers taking place in a vat which fills up with suspension at each layer formation.
Thus, according to the invention, the deposition of suspension can be carried out in a controlled manner, advantageously over the entire width and length of the layers without excess suspension as in the previously described situations of the prior art.
Moreover, the progressive filling of the vat offers advantages compared to the case of working with a vat initially filled with the suspension into which a plate supporting the stack is lowered step by step at each layer formation in order to cover the layer with a cured pattern with a new layer to be irradiated. These advantages are to avoid a drop in the reactivity of the suspension as a result of an exchange with the ambient temperature, to avoid sedimentation of the ceramic or metallic part of the suspension at the bottom of the vat, and to avoid a high shear stress which would be necessary to lower a too high viscosity level of the suspension to allow it to cover the layers to be irradiated.
The object of the present invention is therefore a machine for manufacturing parts by the stereolithography technique, according to which layers of radiation-curable suspension are successively cured one on top of the other by irradiation according to a pattern defined for each layer, said machine comprising:
According to a particular embodiment of the machine according to the invention, said at least one vacuum forming device is connected to a vacuum tapping to control the amount of suspension released from said at least one hole.
The applicator may be a rectangular parallelepiped, the active face facing the horizontal receiving surface being the release face of the applicator in which said at least one hole is formed.
Said at least one formed hole, which is formed in the active face, may be constituted by a single slit formed over the entire width of the active face of the applicator or by a plurality of holes uniformly distributed over the entire width of the active face of the applicator.
The suspension can be supplied to the suspension reserve by a number of feeds from the external tank, uniformly distributed over the width of the applicator, with internal suspension distribution tubes being able to be mounted dipping into the suspension reserve.
The suspension reserve can advantageously be divided into compartments, each of which is associated with a vacuum formation device by at least one vacuum tapping and at least one supply of suspension from the external tank. Thus each compartment has its own supply system and its own vacuum system. The advantage is that if one compartment becomes empty of suspension for any reason, this does not disturb the others. It has also been found that this arrangement allows for a better control of the level of suspension in the suspension applicator.
The machine may comprise a device for controlling the supply of suspension to the suspension reserve cavity while the applicator is stationary, in particular at a transverse edge of the layers, or during its translational movement. The advantage of supplying suspension while the applicator is moving is to minimise the amount of suspension in front of the applicator, which can cause mechanical stress on the parts or beading problems during curing, generating interference with the applicator later.
The machine according to the invention may comprise a sensor for the quantity of uncured suspension in the vat, and a controller regulating, for each layer, the supply of suspension by the applicator as a function of the level of uncured suspension detected in the vat by the suspension quantity sensor.
The suspension quantity sensor can be one of a level sensor and a volume sensor.
The active face of the applicator may carry at least one blade configured to allow scraping of the suspension deposited through the said at least one hole, the said blade being located set back from the said at least one hole in the direction of movement of the applicator.
The front face of the applicator in the direction of movement may have the form of a pushing shield.
The vat can be equipped with an overflow for discharging excess uncured suspension. The overflow can be controlled as a function of the level of suspension detected by the sensor of the quantity of uncured suspension in the vat.
To better illustrate the object of the present invention, a particular embodiment is described below, by way of indication and not as a limitation, with reference to the attached drawing.
On this drawing:
Referring to
A suspension reserve 6 (
The transverse plates 3 have holes 7 for the passage of fixing screws on an applicator holder 8. The applicator holder 8, with its applicator 1, is slidably mounted on rails 9 which frame a horizontal receiving surface 10 (see
Recesses 11 are provided in the top plate 2, each of which is suitable for receiving an end fitting 12 of a hose 13. The hoses 13 are connected to an intermediate connection 14 from which a hose 15 extends, the two hoses 15 being joined to an intermediate connection (not shown) from which a hose for connection to an external suspension tank (R in
The recesses 11 are each connected to an internal suspension distribution tube 16 which dips into the reserve 6.
The supply of suspension to the reserve 6 is controlled by a device (not shown) which is programmed to open a dispensing valve or valves to supply suspension for example while the applicator 1 is stationary, in particular at a transverse edge of the receiving surface.
The plate 2 also has vacuum tappings 17 which are connected in pairs by hoses 18 to an intermediate connection 19 from which a connection to a vacuum forming device, as shown in
Each of the plates 4 has a scraping blade L along its lower edge in the example shown, this having here the form of a pushing shield (
In the example shown, the suspension applicator has two blades L, each of which is active in one of the two directions of movement.
The machine according to the invention works as follows:
Alternatively, the working surface may be lowered as shown in
Referring now to
Referring to
Referring to
Referring to
Referring to
The components of applicator 1′ identical to those of applicator 1 are designated by the same reference numbers.
The compartments formed by the partitions 20 are of substantially the same volume and each is supplied with suspension by a hose similar to a hose 13 as shown in
In the example shown, the partitions 20 are bevelled at the bottom to facilitate the exit of suspension from each of the compartments.
Not shown in
Thus each compartment has its own supply system and vacuum system, allowing the supply and vacuum to be controlled compartment by compartment.
Also shown in
Chaput, Christophe, Gaignon, Richard, Pastora, Jean, Soumard, Jean Luc, Cointepas, Thomas
Patent | Priority | Assignee | Title |
Patent | Priority | Assignee | Title |
10562226, | Mar 15 2013 | Southern Methodist University | Additive manufacturing of active devices using dielectric, conductive, and magnetic materials |
3051567, | |||
5248249, | Jul 27 1990 | Sony Corporation | Three-dimensional structure forming apparatus provided with a liquid-level control system for a main resin tank |
5922364, | Mar 03 1997 | AAROFLEX, INC | Stereolithography layering control system |
5980812, | Apr 30 1997 | Solid imaging process using component homogenization | |
20050056913, | |||
20070075461, | |||
20110309554, | |||
20160046075, | |||
20170106594, | |||
20170326803, | |||
20170368816, | |||
20180141151, | |||
20180333913, | |||
20180361502, | |||
20190099807, | |||
20210008757, | |||
20210162657, | |||
CA2859414, | |||
CN106622413, | |||
CN208343464, | |||
EP1847377, | |||
JP2012505774, | |||
JP4426060, | |||
JP6305031, | |||
JP8150662, | |||
WO2004061418, | |||
WO2015137184, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Nov 26 2021 | S.A.S 3DCERAM-SINTO | (assignment on the face of the patent) | / | |||
Feb 22 2022 | GAIGNON, RICHARD | S A S 3DCERAM-SINTO | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 059144 | /0632 | |
Feb 22 2022 | CHAPUT, CHRISTOPHE | S A S 3DCERAM-SINTO | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 059144 | /0632 | |
Feb 22 2022 | PASTORA, JEAN | S A S 3DCERAM-SINTO | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 059144 | /0632 | |
Feb 22 2022 | SOUMARD, JEAN LUC | S A S 3DCERAM-SINTO | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 059144 | /0632 | |
Feb 22 2022 | COINTEPAS, THOMAS | S A S 3DCERAM-SINTO | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 059144 | /0632 |
Date | Maintenance Fee Events |
Nov 26 2021 | BIG: Entity status set to Undiscounted (note the period is included in the code). |
Date | Maintenance Schedule |
Oct 24 2026 | 4 years fee payment window open |
Apr 24 2027 | 6 months grace period start (w surcharge) |
Oct 24 2027 | patent expiry (for year 4) |
Oct 24 2029 | 2 years to revive unintentionally abandoned end. (for year 4) |
Oct 24 2030 | 8 years fee payment window open |
Apr 24 2031 | 6 months grace period start (w surcharge) |
Oct 24 2031 | patent expiry (for year 8) |
Oct 24 2033 | 2 years to revive unintentionally abandoned end. (for year 8) |
Oct 24 2034 | 12 years fee payment window open |
Apr 24 2035 | 6 months grace period start (w surcharge) |
Oct 24 2035 | patent expiry (for year 12) |
Oct 24 2037 | 2 years to revive unintentionally abandoned end. (for year 12) |